Design considerations for a dual-etalon seed-light pre-filter for high-energy LCLS applications

A flexible seed-light generation and coherence filtering scheme is considered for a 1.5 إ FEL operating at 15 GeV. For R&D applications the configuration allows the FEL to be operated in a combination of Self-Amplified Spontaneous Emission (SASE) and Coherent Amplifier (CA) modes. Selected design and performance parameters are discussed.